The present invention relates to a golf ball having an excellent rebound.
Efforts to confer golf balls with an excellent rebound have until now focused on and optimized one or more indicator of the polybutadiene used as the base rubber, such as the Mooney viscosity, polymerization catalyst, solvent viscosity and molecular weight distribution. See, for example, Patent Document 1: JP-A 2004-292667; Patent Document 2: U.S. Pat. No. 6,818,705; Patent Document 3: JP-A 2002-355336; Patent Document 4: JP-A 2002-355337; Patent Document 5: JP-A 2002-355338; Patent Document 6: JP-A 2002-355339; Patent Document 7: JP-A 2002-355340; and Patent Document 8: JP-A 2002-356581.
For example, Patent Document 1 (JP-A 2004-292667) describes, as a base rubber for golf balls, a polybutadiene having a Mooney viscosity of from 30 to 42 and a molecular weight distribution (Mw/Mn) of from 2.5 to 3.8. Patent Document 2 (U.S. Pat. No. 6,818,705) describes, for the same purpose, a polybutadiene having a molecular weight of at least 200,000 and a resilience index of at least 40.
However, because many golfers desire golf balls capable of traveling a longer distance, there exists a need for the development of golf balls having an even better rebound.
To improve the resilience of the core, Patent Document 9 (JP-A 2-297384), for example, discloses art involving the addition of an organosulfur compound to the core material. Regarding the preparation of organosulfur compounds, preparation processes have been disclosed in which the solvent used has been improved (e.g., Patent Document 10 (JP-A 48-8739) and Patent Document 11 (JP-A 54-30127)).
Yet, there continues to be a desire for golf balls having an even higher rebound than golf balls which use the foregoing core material.
Patent Document 1: JP-A 2004-292667
Patent Document 2: U.S. Pat. No. 6,818,705
Patent Document 3: JP-A 2002-355336
Patent Document 4: JP-A 2002-355337
Patent Document 5: JP-A 2002-355338
Patent Document 6: JP-A 2002-355339
Patent Document 7: JP-A 2002-355340
Patent Document 8: JP-A 2002-356581
Patent Document 9: JP-A 2-297384
Patent Document 10: JP-A 48-8739
Patent Document 11: JP-A 54-30127